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        // function haha(){
        //     console.log("this is haha")
        // }();

        // 以上写法是不行的，得需要小括号包裹起来
        // 写法1
        (function haha() {
            console.log("this is haha")
        })();
        // 写法2
        (function haha() {
            console.log("this is haha")
        } ());
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